Engine struggling to start

First of all, sorry for my very poor knowledge on cars… I’ve only just got my car back from the garage and didn’t want to have to send it straight back.

Make + Model: Vauxhall Corsa 2003 (1.2L)

I’ve been experiencing an issue where the car seems to be struggling to start up, when I turn the electric on the engine lights flash at an inconsistent pattern. A faint noise can be heard along side this as well, now sometimes the engine starts up, sometimes it turns over but just doesn’t start. One factor that I’ve noticed is that the temperature effects this, when the outside temperature is lower than 5 degrees Celsius it likely won’t start. Anything over and even though the flashing lights are still there, it does manage to start.

Any ideas on what might be causing this would be appreciated, I will have to take it back to the garage but just want to see if I can get an idea to what is wrong with it. My instinct tells me either a battery/alternator problem but I’m likely wrong.

Video 1 (Flashing engine light, car does not start):

Video 2 (Flashing engine lights, car does start):

The problem may be caused by a bad BCM.

Tester